Electromagnetic Acoustic Transducers for Robotic Nondestructive Inspection in Harsh Environments.

摘要: Elevated temperature, gamma radiation, and geometric constraints inside dry storage casks for spent nuclear fuel represent a harsh environment nondestructive inspection of the cask require that be conducted with robotic system. Electromagnetic acoustic transducers (EMATs) using non-contact ultrasonic transduction based on Lorentz force to excite/receive waves are suited use in inspection. Periodic permanent magnet EMATs actuate/receive shear horizontal guided developed application stress corrosion cracks heat affected zone welds stainless steel canisters. The EMAT’s components carefully selected consideration environment, tested under elevated temperature radiation doses up 177 °C 5920 krad, respectively, evaluate performance realistic environmental conditions. effect is minimal, but by temperatures above 121 due low Curie magnets. Different magnets needed operate at °C. capability detect notches also evaluated from B-scan measurements 304 welded plate containing surface-breaking notches.